diff --git a/java/ql/src/utils/model-generator/CaptureSinkModels.ql b/java/ql/src/utils/model-generator/CaptureSinkModels.ql
index d3a12bfdf25..af9676115a2 100644
--- a/java/ql/src/utils/model-generator/CaptureSinkModels.ql
+++ b/java/ql/src/utils/model-generator/CaptureSinkModels.ql
@@ -28,7 +28,7 @@ class PropagateToSinkConfiguration extends TaintTracking::Configuration {
 string asInputArgument(Expr source) {
   result = "Argument[" + source.(Argument).getPosition() + "]"
   or
-  result = source.(VarAccess).getVariable().toString()
+  result = "Argument[" + source.(VarAccess).getVariable().(Parameter).getPosition() + "]"
 }
 
 string captureSink(Callable api) {
diff --git a/java/ql/test/utils/model-generator/CaptureSinkModels.expected b/java/ql/test/utils/model-generator/CaptureSinkModels.expected
index a2d942d75da..dc043549bcf 100644
--- a/java/ql/test/utils/model-generator/CaptureSinkModels.expected
+++ b/java/ql/test/utils/model-generator/CaptureSinkModels.expected
@@ -1,3 +1,3 @@
 | p;Sinks;true;copyFileToDirectory;(Path,Path,CopyOption[]);;Argument[1];create-file; |
-| p;Sinks;true;readUrl;(URL,Charset);;url;open-url; |
-| p;Sources;true;readUrl;(URL);;url;open-url; |
+| p;Sinks;true;readUrl;(URL,Charset);;Argument[0];open-url; |
+| p;Sources;true;readUrl;(URL);;Argument[0];open-url; |